The present invention relates generally to motion detecting apparatus, and more particularly provides a compact hand controller in which all, moving parts of a unique six-degree-of-freedom motion sensing system are positioned within a hollow, spherical hand-held motion input member, the sensing system having an output portion, remote from the spherical member, which generates signals indicative of the magnitude and sense of translation and rotation of the spherical member relative to three mutually perpendicular reference axes.
Conventional motion detecting systems typically comprise an input member (often hand-operable), a sensing system which detects motion of the input member relative to one or more reference axes, and an output system which generates a signal or signals indicative of the sensed motion of the input member. Various of these conventional motion detecting systems are exemplified in U.S. Pat. Nos. 3,229,590; 3,420,147; 3,573,412; 3,776,058; 3,918,496; 4,216,467; 4,320,392; 4,536,746; 4,404,991; and 4,555,960.
This general motion-detecting scheme is incorporated into a number of well known devices such as joy sticks, track balls, the computer "mouse", light or sound pens, arm digitizers and free space digitizers.
Joy sticks are devices used to generate translational motion signals relative to two perpendicular axes by pivoting an elongated rod member around such axes. Some units have the capacity for generating a third motion signal by rotating the rod about its longitudinal axis.
Track balls operate similarly to joy sticks except that the two directional output signals are generated by rotating the ball about two perpendicular axes thereof. Some track ball units have the capability of generating a third direction signal created by rotating the ball about a third axis thereof.
The familiar computer "mouse" is a device in which translational directional signals relative to two perpendicular axes are generated by moving a "puck" around on the flat surface of a sensing table. Light or sound pens are devices similar to the computer mouse except that a "pen" is moved around on a CRT or other flat surface.
The arm digitizer is a device that allows the location of a point in three dimensional space by the use of a series of arms linked to a pointer, an output system generating directional signals which are correlated to the measured angles of the various arms as the pointer is moved.
Free space digitizers are devices in which the position of a pen-like device in three dimensional space is measured by the use of an electro magnetic field created by a coil in the pen, and pickup coils located in a sensing table.
Despite their wide use and acceptance, however, all of the foregoing motion detecting devices have associated therewith certain limitations and disadvantages.
For example, in each of the devices the motion sensing system is usually wholly external to the hand-held motion input member. This separation of the input member and its associated sensing system accordingly increases the necessary overall volume of the particular motion detection system. Additionally, many conventional motion detecting systems utilize rather sophisticated (and therefore relatively costly) electronic circuitry in their motion-sensing systems, or alternatively utilize fairly bulky mechanical linkage mechanisms which are subject to wear-induced inaccuracies.
Further, many of the simpler motion detecting systems, as mentioned above, have only two or three degrees of motion input freedom. Devices like the computer mouse, the light or sound pen, and the free space digitizer can additionally require a considerable amount of table space.
From the foregoing it can be seen that it would be desirable to provide compact motion detecting apparatus and associated methods which eliminate or substantially minimize above-mentioned and other limitations and disadvantages associated with conventional motion detecting systems. Accordingly, it is an object of the present invention to provide such apparatus and methods.